1. Field of the Invention
The present invention relates to a slurry for preparing cosmetic products and to such cosmetic products made through the use of this slurry. More specifically, the present invention provides a process for making smooth, adhesive, spreadable, long-lasting cosmetic products for external use, such as solid or solid-like, cake cosmetic products, such as make-up preparations.
2. Prior Art
Solid or solid-like, cake cosmetic products, such as make-up preparations (e.g. face powder, powder foundation, eye shadow, mascara, rouge and the like) are conventionally produced by filling a cosmetic powder into a metal or plastic pan or case followed by molding the powder by a press. In particular, the conventional manufacturing process for preparing cosmetic products includes mixing pigments and extender pigments and then atomizing them until the colors are well dispersed and uniform. Oily components and auxiliary agents, such as anti-bacterial agents, are added to the pigments and extender pigments and mixed and are atomized to disperse the oily components. The resulting mixture is then screened and further mixed until a uniform cosmetic powder is obtained. The cosmetic powder is filled into a pan or case and molded by a press.
This conventional process has several disadvantages:
i) Pigments and extender pigments have inherent strong hydrophilic properties; thereby, they will fade and/or discolor when contacted by perspiration, unless they are specially treated. PA1 ii) The percentage of out-of-specification product is unacceptably high due to the non-uniformity of surface-color and/or surface-hardness of the molded cosmetic product. PA1 iii) Multi-color molding and complex shape molding are quite expensive because of the cost of the shaping-mold, typically machined from metal. PA1 iv) High labor costs are incurred, arising from the manual labor needed for adjustment and maintenance of equipment and the supply of bulk powder. PA1 v) The loss of cosmetic powder during the molding process is significant. PA1 vi) The work environment is undesirable due to the exposure of the workers to powdery dusty pigments and extender pigments.
It has previously been proposed to use pigments that have been made hydrophobic to solve the problem (i). For example, pigments or extender pigments and/or substrates that are surface-treated with silicone are strongly hydrophobic and can be used to prevent color fading and to improve the duration of use before reapplication. They can also be used for two-way cake (wet/dry application) cosmetics.
While the use of polysiloxanes ameliorates problem (i), the molding process becomes more complex and time consuming, and problems (ii), (iii), (iv), (v), and (vi) remain unsolved.
There have been some suggestions to solve problems (ii), (iii), (iv), (v), and (vi). For example, Japanese Patent 07-29904 and U.S. Pat. No. 4,967,810 suggest the use of a slurry in which pigments, extender pigments and/or substrates, and oily components are dispersed in an organic solvent for injection into the pan or case by an injection machine. These proposals may reduce the severity of problems (ii), (iii), (iv), and (v), but problem (vi) remains unsolved. Importantly, the use of organic solvents raises concerns about the possible dangers of flammability, environmental pollution, and harmful effects on the human body. Further, the choice of usable oily components is restricted depending on the kind or nature of the organic solvent used. For example, non-uniformity of the product is observed when an alcohol is used as the organic solvent with a silicone oil as the oily component of the cosmetic product.